Among transmitters that generate modulated signals by superimposing data signals onto carrier signals and then transmit the generated modulated signals such as in broadcasting on medium-frequency; there are transmitters which generate modulated signals using a plurality of amplifiers having different amplification factors and then transmit the generated modulated signals. In such a transmitter, modulated signals are generated by performing ON/OFF control with respect to big step power amplifiers and binary power amplifiers.
However, in a transmitter, minute information portions of input signals are corrected in the binary power amplifiers. Hence, the speed of ON/OFF operations of the binary power amplifiers becomes fast, thereby leading to a possibility of an increase in the distortion of the modulated signals due to the high-speed operations. In order to reduce the distortion, it becomes necessary use a high-order bandpass filter, which may cause an increase in the circuit size.